Stack elevator for printing machines



Oct. 8, 1957 3 Sheets-Sheet 1 Filed March 3, 1955 Inventor? Koc/f Br/MiQ-H HT'TORAAE) Oct. 8, 1957 w. KOCH STACK ELEVATOR FOR PRINTING MACHINES a Sheets-Sheet 2 Filed March 3, 1955 fm/eman A/A'RNER Koc/l firro mvar Oct. 8, 1-957 w. KOCH STACK ELEVATOR FOR PRINTING MACHINES Filed March 3, 1955 3 Sheets$heet 5 2 \v 2, l w q TMv K I -h||l l 3 V u 0 a 5 MW 2 f 2 w w W m}@ v EM wz m W m m M v Zr w I 1 [ice 2,809,034

Patented Oct. 8, 1957 STACK ELEVATOR FOR PRINTING MACHINES Werner Koch, Offenbach (Main), Germany, assignor to Faber & Schleicher Aktiengesellschaft, a German body corporate Application March 3, 1955, Serial No. 492,002

Claims priority, application Germany March 12, 1954 7 Claims. (Cl. 271-62) This invention has reference to machines for printing on sheets and it more particularly relates to devices in such machines which are provided to feed and exchange the stacks or piles of sheets while the machine is in operation.

In devices of this kind it is a known practice, after the major part of the sheets in a stack has been fed to the printing mechanism of the machine, that is, after the stacking table has been lifted to a certain height, to support the stacking table and the remaining part of the stack resting thereon by additional means which are timed to become effective at the correct moment or put into operation by hand. The lifting means for the stacking table, for example a set of chains, then move downwardly in order to seize a new stacking table which had meanwhile been introduced to the stacking device, carry it upward until its top sheet contacts with the table of the foregoing stack, and continue its lifting movement. When the table of the foregoing stack eventually comes free of the additional support, it can be taken out of the device.

This known arrangement has the serious disadvantage that during the removal of the foregoing stacking table the remaining stack or pile of sheets drops by an amount corresponding to the height or thickness of the table. In order to avoid as far as possible the disturbances in the separation and the feed of the sheets due to this cause, the stacking tables are made as thin as possible. But since in the modern rapid stack changing devices the table is freelysuspended by the hoisting chains at only its four corners, they cannot be burdened with a heavy load of sheets due to the excessive deflection of the table. It is for this reason that on a weak table of this description and on account of the deflection of the table becoming increasingly troublesome, this kind of device is limited only to machines such as are used for small size sheets and moderate stacking heights. It has been proposed to use the thin tables only to serve as auxiliary tables and to support them by a strong main table, which latter is removed immediately prior to the reception of the remaining stack by the additional supporting means. Such a stacking device, however, is too awkward and diflicult to handle, since the removal of the heavy main table re quires a considerable amount of strength on the part of the operator.

A frequently adopted way, namely the supporting of the stacking table on loose rails which are suspended in the hoisting chains, is impracticable because of its handling being too time-consuming as to comply with modern requirements which demand a quick exchange of the stacks and stacking tables While the printing machine remains at work.

The invention now aims at the removal of the aforesaid drawbacks and in its more general aspect consists in the provision of a stack exchanging device in which the exchange of the stacking tables can be performed quickly, reliably and at great ease of handling, and in which sheets of any size and in any height of stacks can be handled without difliculty.

A further object of the invention rests in the provision of particularly strong carrying means for the stacking table of such kind which will close under the table when lifting the stack or pile into the printing device, and which will open out on its return movement in order to move past the table and to close again after having passed it. A still further object of the invention is the provision, at the top of the stacking device, of additional supporting means for the stacking table to seize and support the latter after it has been fed to the corresponding height, and of means operating in dependence thereof, for returning the stacking table carrying means at increased speed.

Other objects of the invention are the provision of mechanical and electrical means for controlling the movement of the various elements of the stacking device so as to proceed in proper sequence and mutual corelation and to reliably prevent any interruption in the operation of the machine during the feed or the exchange of the stacks.

With these and other objects in view the invention broadly consists in the provision of a sheet stacking device having a vertically slidable main stack table and stack table supporting rails which are adapted to move outwardly when reversing from their upper to their lower position, and to move inward again under the new stacking table when in its lowest position.

The invention further consists in the provision of pawlshaped rockable lever arms for the temporary support of the stacking table in its highest position, of means for guiding the supporting rails downwardly in extended position, of other means for moving the front stops for the stack out of the way when the extended supporting rails are moving downwardly, and of control means for raising, lowering and reversing the supporting rails in the performance of their function.

In a preferred embodiment of the invention the laterally movable stacking table supporting rails are arranged parallel to the longitudinal edges of the stacking table and so as to support the said table as far inwardly as possible in order to cause the table plate to deflect, if at all, about both its centre and its sides to approximately the same degree, and to thus keep the deflection down to about its lowest possible amount.

The deflection may be further decreased by making the supporting rails comparatively broad, or they may be enlarged beyond their normal width as for example by imparting to them the shape of an ellipse, which would sustain the stack table particularly at the place where the degree of deflection is greatest.

A particularly effective and yet simple arrangement has been devised in which two parallel stacking table supporting rails are provided, which are substantially U-shaped with the closed part of the U depending downwardly while the upper, open ends are connected to the hoisting chains of the stacking table and which, during their downward movement, can be swung out about two mutually opposing table edges.

The aforesaid additional means for the supporting of the nearly used-up stack during the descent of the hoisting means and the lifting of a new stack, are preferably in the shape of pivoted or otherwise movable pawl-shaped lever arms, which support the stacking table in its highest position and to which, in order to avoid disturbances,

an additional movement in the direction of stack feed may of the stack front, the invention provides for making these stop bars movable in such a manner as to enable them, in dependence of the seizure of the nearly usedup stack by the aforesaid additional supporting means, to recede automatically away from the stackand to thereby enable the supporting rails to swing sideways and to then move downwards undisturbed by the said stop bars. After the supporting rails having moved to their lowermost position, the stop bars are automatically returned into their stack aligning position.

A stacking device constructed and arranged in accordance with the invention is illustrated in the accompanying drawings by way of example. In these drawings,

Fig. 1 represents a front elevation of the new stacking device,

Fig. 2 is a side view of Fig. 1, partly in section,

Fig. 3 is a view similar to Fig. 2 with the stacking table supporting rails in their highest position, while Fig. 4 illustrates in full lines the position of the stacking table supporting rails which in Fig. 2 is indicated in broken lines.

Provided in the side walls 1 and 2 of the stacking device are guide columns 3 on which sockets 4 are slidable, being moved up and down by a set of endless chains 6, to which the sockets are attached as by means of lugs 5. The chains travel in the usual manner over sprockets 7 which, in turn, are rotated through worm gears 8 by a shaft 9 from a stack lifting gear which is arranged in the housing 10 at the top of the device. Idling sprockets 11 are provided at the bottom of the stacking device over which the lower loops of the chains 6 are passed.

The sockets 4 are provided with dowel pins 12 on which are pivoted the arms of depending U-shaped supporting rails 13 for the stacking table 14, which latter, for the purpose of reducing deflection, is strengthened as by means of angle irons 15. The stack 16 is fed upward in substantially known manner until its supporting table 14 encounters the depending pawl-shaped heads of the lever arms 17 which serve as the additional supports for the stacking table when the latter has approximately reached its highest position. When the table 14 settles on the pawl heads on the lever arms 17 it actuates by its weight an electric switch 18 which immediately causes the drive of the hoisting chainsfi to reverse so that the sockets 4 together with their U-shaped rails 13 are returned downwardly at increased speed.

Since in the meantime a new stack 19 has customarily been placed on the platform 20 in the stacking device underneath the nearly used-up stack 16, it is necessary that the supporting rails 13, prior to their downward movement, should be moved out of the way of the new stack 19 and its table 21. For this purpose guide bars 22 are provided which are adapted to cooperate with rollers 23 on the arms of the supporting rails 13. The upper end of each guide bar 22, as shown in Figs. 2, 3 and 4, cranked-off inwardly about a pin 24 and arranged to form a one-way switch 25. In the up movement of the supports 4, 13 the switch 25 gives way so as to let the roller 23 pass, while in the downward movement of the parts 4, 13 it guides the roller to the outside of the guide bar 22 as indicated by the dotted position 13 and 23 in Fig. 2, and in full lines in Fig. 4. When in this position the rails 13 are moved downward until their rollers 23 have reached the slightly curved lower end of the guide bars 22. In this position, which is indicated at the bottom of Fig. 3, they pivot inwardly by reason of their own weight, which may be accentuated by a spring, and take their initial working position below the new stacking table 21.

Shortly before the rails 13 reach their lowest position, a projection 26 on the socket 4 at the left hand side of Fig. 1 encounters the lever 27 of a reversing switch 28, which turns the downward movement of the supporting rails into an accelerated upward movement. In this way the new stack 19 is lifted until it comes into contact 4 with the table 14 above, which becomes slightly lifted off the pawls 17. Thereby the contact 18 opens and the accelerated upward movement is interrupted, while the ordinary automatic feed is initiated in dependence of the normal supply of the sheets in the printing operation.

Provided in connection with the stacking device are the stop bars 32 for the alignment of the stack front. These stop bars, in accordance with the invention, are made to consist each of a short stationary upper part 29 which is fastened to a girder 40, and a movable major portion 32 which is carried by links 30 and 31. In their working position the stop bars 32 are sustained by projections on the catch levers 33 and the links 30 as illustrated in Fig. 2. When the supporting rails have reached their upper position and the contact 13 has become closed by the table having seated itself on the pawl 17, this closes an energizing circuit for the magnet or solenoid 34 simultaneously with the initiation, as aforesaid, of the downward travel of the supporting rails, and the catch bar is pulled away from the link 30 against the action of its spring 35. The locking action of the link 33 having thus been rendered ineffective, the stop bars 32 are able to swing by their own weight on their links 30, 31 about the pivots 41, 42 into the position shown in Fig. 3, in which there is now sufiicient clearance between the bars 32 and 22 for the rails 13 to pass, as is indicated by the position 13 at the bottom of Fig. 3. Shortly before the sockets 4 reach their lowest position, a projection 36 of the socket on the left hand side of Fig. 2 comes into contact with a lever 37 at the bottom of that figure and turns it out of the position which is shown in broken lines into that shown in full lines. Lever 37 is fast on a toothed segment 38 and the link 31 on a toothed segment 3), which segments are both in engagement with one another. When the bars 32 are in their dropped position the links 31 take their positions vertical as in Fig. 3, which corresponds to the dotted position of lever 37 in Fig. 2. The action, then, of the projection 36 of socket 4 on lever 37 turns the two segments and, over the links 31, returns the bars. 32 into their effective positions. As simultaneously with the actuation of switch 28 as aforesaid, the energizing circuit of the magnet 34 is interrupted, the catch lever 33 becomes attracted by its spring 35 so as to secure the returned link 30 and, therewith, the stop bars 32 in their raised position as shown in Fig. 2.

What I claim is:

l. In a stack feeding and exchanging device for sheet printing machines having means for feeding a stack of sheets from a stacking table into the printing mechanism of the machine, means for supporting the stacking table of a nearly used-up stack of sheets during the introduction into the device of a new table while the printing mechanism continues its operation, and means for lifting the new stacking table with the new stack thereon into cantact with the foregoing table while the latter is being held stationary, at least two approximately U-shaped supporting rails for the stacking table one at either side thereof, said rails being movable between a table supporting position and a withdrawn position and underlying in the supporting position parts of the table occupied by a stack placed thereupon, individually movable carriers for each of said rails, a pivot on each of said carriers to which the arms of said U-shaped rails are pivotally at tached, means for raising and lowering the said rail carriers and the saidrails attached thereto, a guide post for guiding each of said carriers in their up and down movement, means for swinging and supporting said rails outwardly when in approximately their highest position, and a guide bar in cooperation with each of said rails along which they are returned downwardly in swung-out condition.

2. In astack feeding and exchanging device for sheet printing machines as set forth in claim 1, meansfor moving the stacking table supporting rails out of the path of the stacking table after the table of the nearly used-up stack has been deposited on said additional supports and for returning them at approximately their lowest position to underneath the new stacking table. I

3. A stack feeding and exchanging device for sheet printing machines, comprising a plurality of guide posts, a slidable socket on each of said guide posts, an endless chain for raising and lowering said socket, a stacking table, U-shaped supporting rails for said stacking table pivotally attached to opposite pairs of said sockets, said rails extending across the maximum length of the table and underlying in the supporting position parts of the table occupied by a stack placed thereupon, a roller on each arm of the said U-shaped supporting rails, guide bars extending along the path of movement of the said sockets, a one-way switch at the upper end of each of said guide bars adapted to deviate by contact with the said roller on its upward movement and to remain rigid on its downward movement to swing the said rails out of the path of the stacking table, and means at the ends of said guide bars for allowing the said rollers to return inwardly for the said rails to deposit themselves in working position underneath the said stack table.

4. A stack feeding and exchanging device for sheet printing machines, comprising, means for feeding a stack of sheets from a stacking table into the printing mechanism of the machine, movable U-shaped rails for supporting said stacking table during its feed, said rails extending across the maximum length of the table and underlying in the supporting position parts of the table occupied by a stack placed thereupon, additional supports for supporting the stacking tables of nearly used-up stacks, stop bars for aligning the front of the stacks in the stack feeding device, means for movably supporting the said stop bars, and means for releasing the said stop bars for movement away from the stack front surface synchronously with the table of the nearly used-up stacks being engaged by said additional supports.

5. A stack feeding and exchanging device for sheet printing machines, comprising, means for feeding a stack of sheets from a stacking table into the printing mechanism of the machine, movable U-shaped rails for sup porting said stacking table during its feed, said rails extending across the maximum length of the table and underlying in the supporting position parts of the table occupied by a stack placed thereupon, additional supports for supporting the stacking tables of nearly used-up stacks, stop bars for aligning the front of the said stacks in the stack feeding device, means for movably supporting the said stop bars, the said stop bars being movable by gravity away from the stack front surface synchronously with the table of the nearly used-up stacks being seized by said additional supports, links for pivotally connecting the said stop bars to a stationary part of the stack feeding device, a catch lever in connection with one of said links to sustain said link and said bar in the stack aligning position, an electro-magnet responsive to the additional stacking table supporting means for controlling the movement of the said catch lever into its position away from the stack front to release the bars for gravity movement, and geared means in connection with another of said links for returning the said stop bars into their working position.

6. A stack feeding and exchanging device for sheet printing machines having a vertically movable carrier for the stacking table, supporting rails for the said stacking table hingedly attached to the said carrier, said rails extending across the maximum length of the table and underlying in the supporting position parts of the table occupied by a stack placed thereupon, a slding post for the carrier, means for moving the said carrier up and down the said sliding post, additional supporting means for the tables of nearly used-up stacks, movable front stop bars for aligning the stack front in the said feeding device, said bars being biased into a position away from the stack front surface, links for pivotally connecting the said stop bars to a stationary part of the stacking device, electro-magnetic means for releasing the said stop bars for movement away from the stack front surface synchronously with the table of the nearly used-up stack being seized by the said additional supporting means, geared segments in connection with the lowermost links of the said stop bars, and a lever on one of the said segments in the path of the said stack table carrier to be rocked by the same when approaching its lowest position and to thereby actuate the said segments and links to return the said front stop bars into their working position in contact with the said stack front.

7. A stack feeding and exchanging device for sheet printing machines comprising a stacking table with a stack of sheets thereon, stack aligning movable front stop bars, said bars being biased into a position away from the stack front, a plurality of guide posts, a slidable socket on each of said guide posts, means for raising and lowering said socket, U-shaped supporting rails for the stacking table pivotally attached to opposite pairs of said sockets, said rails extending across the maximum length of the table and underlying in the supporting position parts of the table occupied by a stack placed thereupon, a roller on each arm of the said U-shaped supporting rails, guide bars extending along the path of movement of the said sockets, a one-way switch at the upper end of each of said guide bars for directing the said rails on their downward movement out of the path of the stacking table, means at the lower ends of said guide bars for allowing the said rollers to return inwardly for the said rails to deposit themselves in Working position underneath a newly introduced stacking table, pawl-shaped additional supporting levers at approximately the upper end of the device for temporarily supporting the tables of nearly used-up stacks of sheets, links for supporting the front stop bars in their effective position, electro-magnetic means responsive to the seating of a table on the said additional supporting levers for releasing said stop bars for movement away from the stack front, geared means in connection with other of the said links, and an actuating lever in fixed relation to the said geared means in the path of at least one of said slidable sockets and which, when the said sockets approach their lowest position, is encountered thereby to return the said stop bars into their stack aligning position.

References Cited in the file of this patent UNITED STATES PATENTS 1,490,317 Dudley Apr. 15, 1924 2,094,826 Seybold Oct. 5, 1937 2,204,985 Foweraker June 18, 1940 2,225,007 Gudger Dec. 17, 1940 2,654,602 Backhouse Oct. 6, 1953 2,654,603 Williams Oct. 6, 1953 FOREIGN PATENTS 463,495 Great Britain Apr. 1, 1937 871,158 Germany Mar. 19, 1953 

